Improved intestinal preservation using an intraluminal macromolecular solution: evidence from a rat model.

BACKGROUND: Intestinal preservation injury consists of progressive submucosal edema, with fluid originating both from the lumen and the interstitium. Although vascular flushing aims to control electrolyte shifts in the tissue, the lumen is not addressed, and luminal water and electrolytes enter the tissue during ischemia. Because macromolecular solutions may retain water and electrolytes intraluminally, we investigated whether these solutions administered intraluminally may alleviate preservation injury.
METHODS: Sprague-Dawley rat intestines were perfused with University of Wisconsin solution. After excision of the intestines, we intraluminally introduced solutions containing polyethylene glycol 3350 with high (125 mEq) or low (65 mEq) sodium before cold preservation. Controls underwent only vascular flush. After 8, 14, or 20 hr of cold storage, the intestines were analyzed for extent of tissue injury, water retention, brush-border maltase, and tight junction proteins zonula occludens-1 and claudin-3.
RESULTS: Intraluminal composition changed over time, indicating sodium absorption and potassium secretion. After 8 and 14 hr of cold storage, intestines from the low-sodium group had the best morphology and least edema, followed by the controls. Maltase activity slightly decreased in all groups over time and was not affected by the intraluminal polyethylene glycol solutions. Various degrees of delocalization and degradation of zonula occludens-1 and claudin-3 were recorded within the tight junctions, with the most significant effects in intestines from the high-sodium group.
CONCLUSIONS: Intraluminal macromolecular solutions may modulate the preservation injury in University of Wisconsin- perfused intestines. Low-sodium solutions administered immediately before preservation may improve preservation injury, but high-sodium solutions may be detrimental.